Only run container name detection upon ffmpeg parse failure.

media/base/container_names.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_CONTAINER_NAMES_H_
 #define MEDIA_BASE_CONTAINER_NAMES_H_
 
 #include <stdint.h>
 
 #include "media/base/media_export.h"
@@ skipping 44 matching lines @@
   CONTAINER_SWF,              // SWF (ShockWave Flash)
   CONTAINER_VC1,              // VC-1
   CONTAINER_WAV,              // WAV / WAVE (Waveform Audio)
   CONTAINER_WEBM,             // Matroska / WebM
   CONTAINER_WTV,              // WTV (Windows Television)
   CONTAINER_DASH,             // DASH (MPEG-DASH)
   CONTAINER_SMOOTHSTREAM,     // SmoothStreaming
   CONTAINER_MAX               // Must be last
 };
 
+// Minimum size considered for processing.
+enum { kMinimumContainerSize = 12 };
+
 // Determine the container type.
 MEDIA_EXPORT MediaContainerName DetermineContainer(const uint8_t* buffer,
                                                    int buffer_size);
 
 }  // namespace container_names
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_CONTAINER_NAMES_H_